<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      * {
        margin: 0;
        padding: 0;
      }

      h2 {
        text-align: center;
      }

      .box {
        width: 600px;
        margin: 50px auto;
        display: flex;
        font-size: 25px;
        line-height: 40px;
      }

      .qs {
        width: 450px;
        height: 40px;
        color: red;
      }

      .btns {
        text-align: center;
      }

      .btns button {
        width: 120px;
        height: 35px;
        margin: 0 50px;
      }
    </style>
  </head>
  <body>
    <h2>随机点名</h2>
    <div class="box">
      <span>名字是：</span>
      <div class="qs">这里显示姓名</div>
    </div>
    <div class="btns">
      <button class="start">开始</button>
      <button class="end">结束</button>
    </div>

    <script>
      // 获取数据
      const arr = ['马超', '黄忠', '赵云', '关羽', '张飞']

      // 获取元素
      const uname = document.querySelector('.qs')
      const start = document.querySelector('.start')
      const end = document.querySelector('.end')

      // console.log(uname,start,end);
      let timer = 0
      let random = 0
      // 绑定事件
      start.addEventListener('click', function () {
        timer = setInterval(function () {
          random = Math.floor(Math.random() * arr.length)

          uname.innerHTML = arr[random]
        }, 35)

        if (arr.length <= 1) {
          start.disabled = true
          end.disabled = true
        }
      })

      end.addEventListener('click', function () {
        clearInterval(timer)
        arr.splice(random, 1)
      })
    </script>
  </body>
</html>
